Neurologic deficits after neonatal brain lesions are often less debilitating than after comparable lesions in the adult. As a possible explanation for this phenomenon, numerous experiments have demonstrated neuroanatomical remodelling in response to brain lesions in the newborn. This proposal is designed to examine possible correlations between recovery and neural plasticity using the rodent cerebellar motor system. Many reports have detailed the recovery of functions after cerebellar lesions. Several of these behavioral studies have implicated the cerebral cortex and vestibular system in recovery mechanisms. Data recently obtained in our laboratory concerning axonal sprouting of corticopontine and spinovestibular projections after neonatal hemicerebellectomy have provided anatomical support for these concepts. Supplemental funds for program expansion are requested in order to pursue further these findings. Funds are also requested to purchase fluorescence microscopy accessories in order to implement recently developed neuroanatomical tracing techniques.